I dont understand this error and would like help fixing it.

---> System.AggregateException: One or more errors occurred. (Arithmetic operation resulted in an overflow.)
---> System.OverflowException: Arithmetic operation resulted in an overflow.

This is an error i got and i think its the problem because towards the bottom it says
For the details of why this build failed, please review the whole log above and also see your Compile Errors window.